CALHOUN COUNTY. 9 



ness, and were overlaid by two feet of green shale, which was succeeded by 

 the fine grained light blue limestone of the Kinderhook group. 



At Hamburg this limestone is also exposed, and is about six feet in thick- 

 ness. The upper layers are quite arenacious and pass locally into a quartzose 

 sandstone. From this to Gilead, this limestone was met with at every locality 

 examined, where its proper horizon could be seen, and its characteristic fossils 

 are frequently met with, weathered out on the sloping hill-sides below its out- 

 crop. Just below Gilead, its outcrop trends eastwardly, leaving the river bluffs, 

 and it was next seen a few hundred yards to the eastward of the Salt Spring, 

 on section 16, township 11 south, range 2 west. In this vicinity it is quite 

 silicious, and passes into a sandstone, which is filled with beautiful silicious casts 

 of some of its most characteristic fossils. I am indebted to Mr. Wm. Mc- 

 Adams, of Otterville, in Jersey county, for some of the fossils of this sandstone 

 obtained in the vicinity of the Salt Spring. 



The most southerly point, where we found this limestone exposed on the 

 eastern side of the county, is on the southeast quarter of section 11, township 

 12 south, range 2 west, just above Monterey, where it caps a bluff of Niagara 

 limestone. It is here quite silicious and thin bedded at the top, but becomes 

 more massive below. At Mr. Belt's place, near the north line of section 35, 

 township 11, range 2 west, we found this limestone well exposed, and a quarry 

 opened in it, on our first visit to the county in 1853. The bed is here about 

 twelve feet thick, and the rock is quite evenly bedded, the layers generally 

 ranging from four inches to a foot in thickness. It abounds in fossils, among 

 which are Spirifer Wortheni, Atrypa recticularis, and several species of Za- 

 phrentis and HeliopJiyllum. From this point northwardly, this limestone may 

 be seen outcropping along the base of the bluff, nearly to the north line of 

 township 10 south, range 2 west, beyond which point it was not seen. A half 

 mile above Hardin, it is found overlying the Niagara limestone, the latter for- 

 mation occupying the lower twenty feet or more, above the river level. It is 

 here about eight feet in thickness, the lower portion quite thin bedded, but 

 becoming at the top, a hard grey limestone, in thicker strata. Fossils are quite 

 abundant here, especially corals, which are found weathered out of the lime- 

 stone, and are mingled with the debris composing the shingle of the river 

 bank. This limestone is closely associated with the Niagara group, which it 

 immediately overlies in this county, and its outcrop is entirely restricted to 

 localities where the Niagara limestone also appears above the surface. 



KinderTiook Group. At the base of the Lower Carboniferous series in this 

 State, we find a group of rocks, mainly sedimentary in their origin, consisting 

 of shales, shaly sandstones and thin beds of limestone, but locally becoming 

 quite calcareous, and passing into thin bedded, ash colored, shaly, and magne- 

 sian limestones. At some points in this county, the upper portion of this group 



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